In recent years, the price of personal computers (PCs) have rapidly declined. As a result, more and more consumers have been able to take advantage of newer and faster machines. Computer systems have become increasingly pervasive in our society. But as the speed of the new processors increases, so does the power consumption. Furthermore, high power consumption can also lead to thermal issues as the heat has to be dissipated from the computer system. And unlike desktop computers that are powered by an alternating current (AC) source, notebook computers usually run off a limited battery supply. If a mobile computer is operating at the same performance level as a desktop machine, the power is drained relatively quickly.
In order to extend battery life of mobile computers without widening the performance gap with desktop counterparts and to reduce the power consumption of desktop machines, computer manufacturers and designers have instituted power saving technology. One attempt to reduce power consumption entails the use of low power circuit devices. Another power saving method is to use software in controlling system power and shutting down system devices that are not needed. Several voltage/frequency adjustment schemes including Intel® SpeedStep™ technology have been developed to maximize battery life for mobile processors.
But even as designers slowly reduce the power needs of the overall system, the power requirements of the processor have often remained steady. Furthermore, existing schemes are usually targeted at mobile products. Present methods that implement deep processor operating frequency reductions do so by adjusting the bus ratios. Such methods are not feasible in a server product because of the significant performance impact. New schemes have to be developed to target power reduction at the processor at the desktop and server segments.